Yup, tested this before. Also with quite good hardware (sound card, circumaural quality headphones), between 128kbps and 192 you're already not sure whether there a difference or not, but anything above 192 is really wasted effort.
128kbit sounds so poor that I get a headache from listening to it. There is a tinnyness and high pitched squeal that is like a drill through my head. Maybe it's like using a 14" monitor - if you're so used to hearing low bitrate, it may be hard to notice better quality when you hear it occasionally.
